This invention relates to a wheel end assembly for a vehicle having optional two-wheel/four-wheel drive including wheel bearings used for rotatably mounting a wheel hub to a vehicle frame, and more particularly to the manner of retaining the bearings to the wheel hub.
A recent advance in the development of wheel end assemblies for vehicles having optional two-wheel/four-wheel drive is the inboard positioning of the clutch mechanism. Such is described in the commonly owned U.S. Pat. No. 5,740,895. Whereas previously the axle protruded outwardly into the wheel hub whereat the wheel was mounted and a clutch ring within the wheel hub was actuated to connect and disconnect the axle from the hub, in the ""895 patent the wheel hub is provided with an inwardly extending integral spindle portion and the clutch ring and actuator therefor are positioned at the inboard end of the spindle portion.
In this inboard connection system, the inboard end of the spindle and an adjacent part of the axle are provided with matching splines and the clutch ring traverses between engagement with the splines of one only and then engagement with both spindle and axle.
The wheel hub is rotatably mounted to the vehicle suspension, e.g., the knuckle, with high performance bearings. A primary consideration is the proper mounting of the bearing. They need to be compressed, i.e., preloaded to a precise load, and maintained at that load. In the ""895 patent, preloading is provided by a spindle nut screwed onto the spindle at the outboard end. An integral flange at the inboard end of the spindle provides the splines for clutch ring engagement and also provides a shoulder against which the bearings are compressed.
A subsequent development disclosed in the U.S. Pat. No. 5,984,422 provides an integral flange at the outboard end. The inboard end is splined and a coupler having radially inwardly directed splines is slid onto the splined end of the spindle. The coupler is also provided with radially outwardly directed splines that provide for clutch ring engagement. A nut is screwed onto a threaded portion of the spindle""s inboard end to compress/preload the coupler against the bearings and then the spindle end is roll formed against the nut to secure the nut and thereby maintain the preload on the bearings.
Alternate versions of the ""422 disclosure eliminate the nut and provide and maintain the preload of the bearings through direct roll forming of the spindle against the coupler. It will be appreciated that the manner of mounting the coupler to the spindle must provide rotative driving torque from the axle to the wheel hub which is typically accomplished by a matching spline fit between the coupler and the spindle and between the coupler and the clutch ring.
The present invention is directed to improved and alternative mechanism and structure primarily at the inboard end of the spindle for providing clutch ring engagement and preloading and maintenance of the preload of the bearings.
One version provides roll forming of the spindle end directly against the bearing with a coupler fitted (e.g., spline fit) to the inner diameter of the spindle and wrapping around and outside the roll formed end. (FIGS. 4 and 4a)
A second version provides the inboard end of the inner race of the bearings with inner splines (inwardly directed) fitted to the spindle, and exterior splines for receiving a clutch ring. (FIG. 5)
A third version provides an inner race with screw threads that screw onto the spindle. A lock ring secures the inner race of the bearing at the desired preload and the spindle end is provided with splines for receiving the clutch ring. (FIG. 6)
A fourth version provides a coupler having, e.g., dog lugs in axial engagement with the spindle end. The coupler is compressed against the bearing inner race and is roll formed under a lip provided on the inner diameter of the spindle end. (FIG. 7)
A fifth version provides a coupling that is spline fitted to the spindle and abuts the bearing race. A circular groove at the outer diameter of the spindle end is configured to receive a formed retention ring that is cam fitted to the groove to compress and retain the bearings. A variation to this version is the use of a split ring cam fit to slot and retained by a retainer band. (FIGS. 8 and 8a)
A sixth version provides a groove in the exterior diameter of the spindle end. A coupler slides into place over the groove and is then press fit into the groove and against the bearing race. Splines for clutch ring engagement are subsequently formed into the coupler exterior. (FIG. 9)
A seventh version provides the spindle end with fingers. A coupler has mated slots and slides onto the fingers and against the bearing race. The fingers are then press formed in the manner of a rivet head to secure and retain the preload on the bearings. (FIGS. 10 and 10A)
An eighth version provides spline or screw thread engagement of a coupler onto a spindle end and against the bearing race. Cavities are provided for receiving molten metal when the desired preload is obtained which hardens and fixes the coupler to the spindle. (FIG. 11)
A ninth version provides a desired interfit of a coupler to the spindle end and bearing race whereby as fitted the desired preload is achieved. The coupler is spin welded (friction welded) to the spindle end to maintain the preload. (FIGS. 12, 12A and 12B)
A tenth version provides a formed seat at the end of the spindle for receiving a mated coupler that is compressed against the bearing race and welded (conventional welding) to the spindle end. (FIGS. 13, 13A and 13B)
An eleventh version includes a coupler spine fit to the exterior of the spindle inboard end, a retainer screw threaded to the inner diameter of the spindle end, and a lock washer between the retainer and coupler that locks the retainer at the desired compression. (FIG. 14) This version in particular is also adapted for application to the outboard end of the spindle, i.e., an inboard flange providing a shoulder as illustrated in the ""895 patent. (FIG. 14A)
A twelfth version provides a spindle inner end configured in a polygonal form (hexagonal, octagonal, etc.) or other form such as double D or key and key slot, with a coupler similarly configured and fitted to the spindle end which is then roll formed against the coupler. (FIGS. 15 and 15A)
A thirteenth version provides the spindle end with a negative angle and a coupler is force fit onto the spindle end, e.g. the bearing being cold and the coupler heated to expand the inner circumference. (FIG. 16) Alternatively dowel pins can be force fit into the interfitted coupler and bearing. (FIG. 16A)
The above versions are all directed to the same desired end result, i.e., the preloading of wheel bearings, primarily from the inboard end of a wheel hub extension/spindle; and incorporating a coupler secured to the spindle and designed to be engaged by a clutch ring and thereby secured to an axle for four-wheel drive; and with a retention mechanism that insures retention of the preloaded force against the bearings.